Peritoneal dialysis is a variant of artificial blood cleansing. The patient's peritoneum, which is well supplied with blood, is used as the body's own filter membrane in peritoneal dialysis. During peritoneal dialysis, dialysate is introduced into the abdominal cavity via a catheter. Urine components are removed from the blood in accordance with the osmosis principle and enter the abdominal cavity. After some hours, the dialysate with the urine components is drained from the abdominal cavity.
There are generally different options for carrying out peritoneal dialysis. In continuous ambulatory peritoneal dialysis (CAPD), the patients themselves replace the dialysate approximately four to five times a day. In automated peritoneal dialysis (APD), an apparatus, the so-called cycler, takes over the automatic bag change overnight so that the patient is still independent during the day.
In automated peritoneal dialysis in which the abdominal cavity is filled with the help of the aforesaid cycler, a volumetric control is usually used to ensure that no more than a maximum filling volume is dispensed to the patient. This maximum filling volume amounts, for example, to 3,500 ml in an average adult. As a rule, standardized values are used for the filling volume since the effort for an experimental determination of the filling volume individual to the patient should be avoided.